Electric fuse



June 16, 1925. 1,542,604

H. T. BUSSMANN ELECTRIC FUSE Filed May '7, 1919 Patented June 16, 1925.-

HENRY T. BUSSMANN, OF ST. LOUIS, MISSOURI.

ELECTRIC FUSE.

Application filed May 7,

To all whom it may concern:

Be it known that I, HENRY T. BUSSMAN'N, a citizen of the United States, residing at St. Louis, Nfissouri, have invented a certain new and useful Electric Fuse, of which the. following is a full, clear, and exact description, such as will enable others skilled in the art to make and use the same.

My invention relates to electric fuses and refers particularly to that type of fuse known as the refillable cartridge fuse; yet I do not limit my invention to this type as certain of my improvements are likewise desirable in other types of fuses.

Fiber, which is principally used as a casing for electric fuses, will not hold its threads when used very often. It will shrink and swell, making it difficult to provide removable closures' for the casing that are satisfactory. For this reason I provide a member attached to each end of the casing, preferably ofmetal or other material of unchanging dimensions, for the holding of the closures. I

I arrange this member so that it eliminates the difficulties experienced in holding the terminal against edgewise movement caused by inserting the fuse into the jaws of a fuse block. This edgewise movement results in injury to the fuse link or loosening of its fastenings, resulting in poor contact, and consequent premature burn-out of the fuse link.

This member, also serves to hold the terminals against rotational and sidewise movement. One of these members is attached to each end of the casing and is provided with grooves properly positioned so as to hold the terminals in the same plane.

These and other advantages of my invention will be more readily understood by reference to the accompanying drawings,

which show a preferred embodiment of my invention. In describing the device shown in the drawings hereto attached and described in the specifications, I do not limit my invention to the precise form, shape or construction of the fuse shown, or to the several parts thereof, as various alterations can be made without changing the scope of my invention.

Fig. 1 shows a fuse with a broken-out portion to show the arrangement thereof. Fig. 2 is a perspective view of the member attached to the casing. Fig. 3 is a perspective view showing a termlnal and washer 19199 Serial No. 295,368.

engaging each othert Fig. 4. is a view of the fuse link shown in Fig. 1. Fig. 5- shows a modified form. v

In the drawings, 7 is a casing, preferably of hard fiber. 8 is a member fitted upon the casing and held by means of threads or rivet 9 or both. Upon this member 8 is detachably positioned the cap 11, preferably by means of threads 10. 13 is a flat-blade terminal connected to the fuse link 14 by any suitable means, such as bolts 15.

The member 8 is provided with a non-circular'interior, as, for example, grooves, as shown at 12, to hold the terminal 13 against rotational movement. By reason of the substantial, length of these grooves or non-circular interior, the terminal is substantially held against edgewise'movement. One of these members is attached at each end of the casing with the grooves in the same plane, so as to hold the terminals in alignment.

On the interior of the member I provide bearing points having a spaced relation to each other, between Which points the terminal is positioned with only a limited'clearance. 'When the terminal is subjected to edgewise movement, as, for instance, when a fuse is inserted in the fuse block, the terminal will bear on the points 16, 16 or 17, 17 and b reason of the separation of these points and the small clearance allowed, only a ver limited movement of the terminal is permitted. The member must be made of a material of practically unchanging dimension, so as to maintain these dimensions constant. Fiber, as now made, can not be used for this purpose, as the shrinking or swelling of the fiber would not maintain this constant clearance and would cause the terminals to bind. Obviously, these bearing.

points may be on two different pieces as I accomplish this result by means of bearing points of constant; spaced relation, separated from each other.

In the terminal 13-are lateral channels 18, preferably extending completely around theterminal. 19"is a terminal holding device which is preferably a slotted washer having an opening 20 therein which opening closely fits within the lateral channels 18 and holds ,the terminal against longitudinal movement. By reason of the terminal holding device fitting into the channels, flame and gases have no direct path of escape, but are compelled to follow the angular course of the groove. This is particularly advanta- 45 Where other means are provi ed for takin the casing.

By reason of the grooves in the member, which closely fit about the edges of the terminal, the terminal holding device serves to completely close the case. To provide at all points arestricted indirect path for preventing the escape of gases, I may insert a fitting at the point not covered by the terminal holding device, or I may use two such washers as described, one being laterally fitted at each edge of the terminal.

I have shown these channels 18 to be of a width greater than the thickness of the terminal holding device. This permits the terminal a certain limited longitudinal move- 20 ment. This is done to compensate for the variation in the length of the fusible element comprising the terminals and fuse link, when they are assembled. It is necessary that some clearance be allowed in the holes in the terminals and fuse link for the bolt which fastens them together, and by reason of this clearance such variation in length occurs. Owing to the fact that fiber will shrink in length, there is often a varia- 36 tion in the length of the casing which I am able to take care of by these means.

While I prefer to use grooves on each side of the terminal, it is obvious that a groove on only one side may be used and serve to hold the terminal, but there would be a di rect path for the escape of flame and gases on the ungrooved side. It is also obvious that the terminal holding device can be of other form than that shown, as, for example, a bar, although I prefer the construction shown, as, if a bar were used, the advantage of the complete closure of the case would be lacking. This is also true when the edges of the terminal are not closel surrounded.

care of the variation in length of the fusible element, or where such variations are reduced so as to be negligible, I prefer to make the grooves in the terminal of only such width as to closely fit the terminal-' holding device, instead of being wide enough to serve as a floating element.

To close the case I use the washer 21, preferably of cork, but I do not limit myself 5 to same as leather or felt may also be used.

22 is a closing washer, preferably of metal. These washers are held in position on the terminal and case by means of cap 11.

It is obvious that I may use in my fuse other types and forms of fuselinks.

I claimas my invention: 1 1. In a refillable fuse, a casing,-.a closure, a knife blade terminal, a detachable link holding means therefor, amember permanently fitted upon the casing having its interior arranged to permit the terminal and link holding means to pass through and to removably position it therein against rotational movement.

2. In a refillable fuse, a casing, a closure, members permanently fitted upon the ends of the casing, a fuse element comprising knife blade terminals, fuse link and detachable connections therefor, adapted to be passed through the members and means inside the members for holding the fuse element in one plane.

3. In a fuse, a casing, a cap holding member permanently fitted upon the casing, having grooves in the inner periphery thereof in substantially constant spaced relation to each other and a flat blade terminal positioned and extending within said grooves.

4. In a refillable fuse, a casing, a closure, a member permanently fitted upon the easing, a flat blade terminal positioned within the closure, a link holding means therefor; said means and the terminal being adapted to be passed through the casing and means on the inside of the member for substantially holding the terminal against sidewise movement.

5. In a refillable fuse, a casing, a closure, a cap holding member of practically unchanging dimensions permanently fitted upon the casing, a flat blade terminal and a detachable link holding device therefor adapted to be passed through the casing and means within the member for substantially preventing the Y sidewise and rotational movement of the terminal.

6. In a refillable fuse, a casing, a closure,

a fiat blade terminal and a fusible link detachably connected to the terminal to form a structure which is adapted to be passed through the casing and be removably positioned therein, a member of practically unchanging dimensions permanently fitted upon the casing and adapted to extend about g the terminal, bearing po nts inside the member having a constant spaced relation to each other'between which bearing points' the terminal at its edges is removably positioned, with a certain limited clearance, whereby edgewise movement of the terminal relative to the casing is substantially prevented.

7. In a refillable fuse, a casing, a cap, a cap holding member permanentl fitted upon the casing, a flat blade termina adapted to be passed through the casing, and means integral with the member for preventing the rotational movement of the terminal.

18. In a refillable fuse, a casing, a closure, a flat blade terminal, aca holding member permanently fittednpon t e casing adapted to (permit the terminal to be passed through an having oppositely disposed means within which are removably positioned the ed es of the terminal, and a terminal holding evice holding the terminal to limit its longitudinal movement.

9. In a refillable fuse, a casing, a flat blade terminal, a cap holding member fitted upon the casing, having oppositely disposed means within which are removably positioned the edges of the terminal to prevent rotational movement of the terminal, a terminal holding device fitting about the terminal and closing the casing, and having co-acting means with the terminal to limit its longitudinal movement and means for detachably connecting the cap to the member.

10. In a refillable fuse, a casing, a cap, a flat blade terminal, a terminal holding device adapted to aid as a closure and to be held by longitudinal pressure of the cap, and means on the terminal co-acting with said device for permitting a certain limited longitudinal movement of the terminal relative to said device.

a 11. In a refillable fuse, a casing, a cap holding member permanently attached to the casing, a cap, a flat blade terminal, a terminal holding device aiding as a closure and held by pressure of the cap, and means on the terminal coacting with said device for allowing the terminal a certain limited longitudinal movement relative to said device.

12. In a refillable fuse, a structure comprising a casing and closure therefor, a pair of terminals and a fuse link connected to form a fuse element, there being a lateral channel in a terminal, a terminal holding device engaging said channel and permitting a certain limited longitudinal movement of the terminal relative to the terminal holding device.

13. In a refillable knife blade fuse, a casing, a flat blade terminal having a transverse lateral channel extending substantially about the terminal, a terminal holding device fitting within such channel and providing a restricted indirect exit for the gases when the fuse is ruptured.

HENRY T. BUSSMANN. 

